Okay first thing first, the combination of using TIP41 for npn transistor and 2N2955 for pnp is not a good ideal si,ce they are not complementary to each other. A pair of TIP120 and TIP125 will work better.

You have directly sorted the base of two transistors to your logic pins which is wrong. You should use a base resistor to limit the base current and since you are using two different transistors make sure you select the correct value of resistor for each type. Also you should make the transistor fully saturated, because only then the rated collector current will flow through it. I will not be able to answer how much voltage and current these transistor can hold until you decide the base resistor values.

Regarding the diode yes, you should use a it to suppress voltage spikes.

Another thing to keep in mind is that power transistor will have relatively a larger base current and since we are controlling two transistors make sure your logic pin can source it.And consider the peak current of the motor as well, the collector current should be 125% of the peak current of the motor for safe operation.